Biodegradable racquet string

ABSTRACT

Biodegradable strings, for example, for use in racquet sports, fishing line, and trimming line, are described. The biodegradable string includes a petroleum based material and a biodegradable additive blended with the petroleum based material. The petroleum based material may be nylon, polyester, or polyurethane, and the biodegradable additive may be less than 5% of the racquet string by weight. The biodegradable string may include one or more filaments containing the biodegradable additive. The biodegradable string may be of a round, hexagonal, heptagonal, or octagonal shape, and may be capable of withstanding high tension.

CROSS REFERENCES

The present Application for Patent claims priority to U.S. Provisional Patent Application No. 63/269,082 by Burbary et al., entitled “BIODEGRADABLE RACQUET STRING,” filed Mar. 9, 2022, which is expressly incorporated by reference herein.

FIELD OF TECHNOLOGY

The present disclosure relates generally to synthetically manufactured string.

BACKGROUND

Synthetic strings, such as those used in racquets (e.g., tennis racquets, racquetball rackets, squash racquets, badminton racquets, etc.), fishing line, and trimmer line, may be manufactured by mixing, heating, and extruding a plastic polymer into a desired shape and size. Synthetic strings may generate waste in the form of plastic, which may be non-biodegradable. Common synthetic strings may have a degradation lifetime of approximately 400 to 500 years.

Additionally, synthetic strings may endure constant tension (e.g., during inactivity) and periodic tension (e.g., during active use) during use, particularly when implemented in racquets. A string's durability may be a measure of the string's ability to withstand both constant and periodic tension without failure for a duration. A string's playability may be a measure of the string's ability to retain a desired tension during both constant and period tension over a time span.

SUMMARY

The systems, methods and devices of this disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

The described techniques relate to improved devices, apparatuses, methods, and systems, that support biodegradable string, such as racquet string, among other examples. Generally, the described techniques provide for a racquet string comprising a petroleum based material and a biodegradable additive blended with the petroleum based material.

A biodegradable racquet string is described. The biodegradable racquet string may include a petroleum based material, and a biodegradable additive blended with the petroleum based material.

In some examples of the biodegradable racquet string described herein, the petroleum based material may be nylon, polyester, or polyurethane.

In some examples of the biodegradable racquet string described herein, the biodegradable additive may be between 0.2 percent and 4 percent of the racquet string by weight.

In some examples of the biodegradable racquet string described herein, the racquet string may include a plurality of filaments.

In some examples of the biodegradable racquet string described herein, the plurality of filaments may be wound together.

In some examples of the biodegradable racquet string described herein, the plurality of filaments may be wrapped around one or a center monofilament or a center multifilament.

In some examples of the biodegradable racquet string described herein, each filament of the plurality of filaments may include the petroleum based material the biodegradable additive.

In some examples of the biodegradable racquet string described herein, at least one filament of the plurality of filaments may include the biodegradable additive.

In some examples of the biodegradable racquet string described herein, the racquet string may be a monofilament.

In some examples of the biodegradable racquet string described herein, a cross section of the racquet string may be one of a round, hexagonal, heptagonal, or octagonal shape.

In some examples of the biodegradable racquet string described herein, the racquet string may contain at least one color additive.

In some examples of the biodegradable racquet string described herein, the racquet string may be capable of withstanding at least 120 pounds of tension.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a front view of a racquet containing biodegradable racquet string in accordance with aspects of the present disclosure.

FIGS. 2A-2D illustrates several cross-sectional views of biodegradable racquet string filament configurations in accordance with aspects of the present disclosure.

FIGS. 3A-D illustrates several cross-sectional views of biodegradable racquet string shape configurations in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

Synthetic strings are commonly used for many products, as synthetic strings are generally durable, can be manufactured easily at low cost, and may be used in various industries, such as the fishing industry (e.g., for fishing line or fishing nets), the lawncare industry (e.g., for trimming line), the racquet sport industry (e.g., tennis, racquetball, squash, badminton, etc.), and nets in sports industry (e.g., tennis nets, volleyball nets, badminton nets, soccer nets, basketball nets, lacrosse nets, etc.). Synthetic strings may be manufactured by mixing, heating, and extruding a petroleum based material into a desired size and shape.

Conventionally, synthetic strings may be nonrecyclable or may have a long degradation lifetime (e.g., approximately 400-500 years). A racquet string may be interwoven (e.g., strung) into the head of a racquet (e.g., a tennis racquet, racquetball racquet, squash racquet, badminton racquet, etc.) in a desired pattern and at a specific tension. Under consistent active use, the racquet string may experience mechanical failure (e.g., breaking) and a new racquet string may need to be interwoven back into the head of the racquet. Racquet string may be discarded after use, generating waste in the form of plastic.

Some plastics, however, may be biodegradable. For example, biodegradable plastic may be made of bioplastics, where the components are derived from renewable raw materials, or plastics made from petrochemicals with biodegradable additives that enhance the biodegradation of the polymers by allowing microorganisms to utilize the carbon within the polymer chain as a source of energy. Examples of biodegradable additives include starches, certain microbial strains, and pro-oxidant additives (e.g., iron, manganese, and cobalt). However, the current racquet strings do not include biodegradable additives and therefore generate plastic waste once discarded.

In accordance with aspects of the present disclosure, synthetic string (e.g., for use in racquet sports, fishing line, fishing nets, trimming line, or sports nets) may be manufactured using a petroleum based material and a biodegradable additive blended with the petroleum based material. The addition of the biodegradable additive may result in the synthetic string having a significantly shorter degradation lifetime relative to traditional racquet string. In some examples, the biodegradable synthetic string may biodegrade in approximately 3 to 5 years. For example, a nylon string with a biodegradable additive has been shown to biodegrade by 10.8% within 121 days. The addition of a biodegradable additive does not change the manufacturing process of synthetic string aside from the addition of the biodegradable additive during the mixing process. In some cases, for example during an extrusion process biodegradable synthetic string may be formed into a desired shape and size and/or be configured for use in several filament arrangements. Additionally, biodegradable synthetic string may have other unexpected advantages beyond biodegradability, not limited to greater durability, and playability or comfort for the user for racquet string.

Aspects of the disclosure are initially described in the context of racquet strings. Examples of racquet strings and methods of manufacturing racquet strings may be described. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams that relate to racquets and racquet strings.

This description provides examples, and is not intended to limit the scope, applicability or configuration of the principles described herein. Rather, the ensuing description will provide those skilled in the art with an enabling description for implementing various aspects of the principles described herein. As can be understood by one skilled in the art, various changes may be made in the function and arrangement of elements without departing from the application.

FIG. 1 illustrates an example racquet 100 that supports biodegradable racquet string 105 in accordance with aspects of the present disclosure. The example racquet 100 may be an example of any racquet utilized in racquet sports, such as a tennis racquet, racquetball racquet, squash racquet, or badminton racquet. The racquet 100 may include a frame including a head 110, a throat 115, and a handle 120, where the head 110 is connected to the handle 120 via the throat 115. The racquet string 105 may be threaded through the head 110 of the racquet via openings 125. In some cases, such as in tennis racquets, the openings 125 may include a gromet 130 (e.g., a plastic cylinder placed in the head 110 of the frame) to facilitate the racquet string 105 through the hole 125 without placing direct stress on the racquet frame.

The racquet string 105, illustrated in racquet 100 as interwoven in the space of the head 110, may be manufactured using conventional techniques. Conventional racquet strings, for example, may be manufactured by blending petroleum based material under high temperatures, then extruding the resulting blend through a nozzle to a desired size and shape (e.g., a filament).

As described herein, the petroleum based material may be blended with a biodegradable additive under high temperatures and then extruded to a desired size and shape (e.g. a biodegradable filament). In some examples, the petroleum based material may be one of nylon, polyester, or polyurethane. In some examples, the biodegradable additive may be between 0.2% and 4% of the racquet string (e.g., the total blended mixture of the petroleum based material and the biodegradable additive) by weight. In some implementations, the blended mixture of petroleum based material and the biodegradable additive may further include one or more color additives. In some cases, no color additives may be included.

In some cases, the racquet string 105 may be interwoven (e.g., strung) at a specified tension to the head 110. The racquet string 105 may retain and withstand constant and periodic tension.

The addition of the biodegradable additive to synthetic string has been shown to increase the durability of the synthetic string. For example, synthetic sting including a biodegradable additive was tested under a knot test and under a tensile strength test compared to control synthetic string that was identical in all aspects except that the control synthetic string did not include the biodegradable additive. In the tensile test, a 3 inch long string is clamped at both ends, and tension force is applied to the string. In a knot test, a knot is tied in a 3 inch long string, the string is then clamped at both ends, and tension force is applied to the string. The control synthetic string was a polyester based string having a diameter of 1.28 millimeters (mm). The biodegradable synthetic string was identical to the control synthetic string (polyester based and having a diameter of 1.28 mm, except that the biodegradable synthetic string included a biodegradable additive of 1% by weight. Under these conditions, the control synthetic string was shown to break under the tensile test at an average of 138 pounds of force, which the synthetic string with the biodegradable additive was shown to break at an average of 150 pounds of force. Accordingly, the addition of the biodegradable additive increased the performance of the synthetic string under a tensile test by 8%. For the knot test, the control synthetic string was shown to break under the tensile test at an average of 92 pounds of force, which the synthetic string with the biodegradable additive was shown to break at 99 pounds of force. Accordingly, the addition of the biodegradable additive increased the performance of the synthetic string under a knot test by 7%. These results show that the addition of the biodegradable additive increases the tensile strength and durability of synthetic string, in addition to decreasing the biodegradation time of the plastic material of the string. These results were not expected or predictable, as the addition of the biodegradable additive was expected to reduce the biodegradation time, but not enhance the strength, durability, or playability of the string.

When applied to racquet sports, this increase in tensile durability resulting from the addition of the biodegradable additive may result in several advantages. For example, the increased tensile strength may result in less frequent changing of racquet string, which may result in time saving and in less plastic waste. Further, increase tensile strength may result in increased consistency in the racquet string tension, which may enable more consistent player feel. Further, the increase knot test durability may show a decrease susceptibility to broken strings, which may result in less frequent changing of racquet string, which may result in time saving and in less plastic waste. When applied to fishing line, the increase in tensile strength of the string may enable the use of smaller gauges of fishing line, which may result in the use of the less plastic material. Further, fishing line that includes biodegradable additives may be less likely to break.

As described herein, although described with reference to racquet string, biodegradable synthetic string may be used for any purpose for which synthetic string is used, for example, for fishing line or trimming line.

FIGS. 2A-2D illustrate several cross-sectional views of biodegradable synthetic string 200 (e.g., racquet string) in accordance with aspects of the present disclosure. As illustrated, FIG. 2A, FIG. 2B, FIG. 2C, and FIG. 2D depict various implementations of synthetic string 200. The synthetic string 200 may include one or more filaments 205 (e.g. an individually extruded mixture of the biodegradable synthetic string 200) and an outer casing 210. Though illustrated in each of FIG. 2A, FIG. 2B, FIG. 2C, and FIG. 2D, the outer casing 210 may not be present in some implementations of biodegradable synthetic string 200. Furthermore, each of FIG. 2A, FIG. 2B, FIG. 2C, and FIG. 2D may represent a possible filament configuration, not limited to the whole applicable scope of biodegradable synthetic string 200.

In some cases, the synthetic string 200 may include one or more filaments 205, where one or more of the filaments 205 may be manufactured to contain the petroleum based material and the biodegradable additive. In some examples, the synthetic string 200 may contain one or more filaments 205 and each filament 205 may be biodegradable. In some examples, the synthetic string 200 may contain one or more filaments 205 where every filament 205 may not be biodegradable. In some cases, the outer casing 210 may be made from the petroleum based material and the biodegradable additive. In other cases, the outer casing 210 may not contain the biodegradable additive. Though illustrated in FIG. 2 as circular in shape, the filaments 205 may have a plurality of sides (e.g., such as in a round, hexagonal, heptagonal, or octagonal shape).

FIG. 2A illustrates a monofilament configuration of the synthetic string 200. In the monofilament configuration, a singular filament 205-a is present and an outer casing 210-a may cover the exterior of the singular filament 205-a. In some cases, the monofilament configuration may not utilize the outer casing 210-a and may instead include only the singular filament 205-a.

FIG. 2B illustrates a center multifilament configuration of the synthetic string 200. In the center multifilament configuration, multiple filaments 205-b of a same size and shape may be wound together and an outer casing 210-b may cover the exterior of the filaments 205-b. In the center multifilament configuration, one filament 205-b 1 may be at the center of the synthetic string 200 and multiple filaments 205-b 2 may be wrapped around the one center filament 205-b 1. In some cases, the center multifilament configuration may not utilize the outer casing 210-b and may instead include only the multiple filaments 205-b. In some examples, all of the filaments 205 may include biodegradable additives (e.g., all of the filaments may be biodegradable). In some examples, less than all of the filaments 205 may include biodegradable additives.

FIG. 2C illustrates a center monofilament configuration of the synthetic string 200. In the center monofilament configuration, multiple filaments 205-c 2 of a same size and shape may be wound together around a center monofilament 205-c 1 of a different size or shape, and an outer casing 210-c may cover the exterior of the filaments 205-c 2. In some cases, the center monofilament configuration may not utilize the outer casing 210-c and may instead include only comprise the multiple filaments 205-c wrapped around the center monofilament 205-c 1. In some examples, all of the filaments 205 may include biodegradable additives (e.g., all of the filaments may be biodegradable). In some examples, less than all of the filaments 205 may include biodegradable additives. For example, in some cases, the center monofilament 205-c 1 may include a biodegradable additive and the filaments 205-c 2 may not include a biodegradable additive. In some cases, the center monofilament 205-c 1 may not include a biodegradable additive and the filaments 205-c 2 may include a biodegradable additive.

FIG. 2D illustrates a multifilament configuration of the synthetic string 200. In the multifilament configuration, multiple filaments 205-d of a same size and shape may be wound together and an outer casing 210-d may cover the exterior of the filaments 205-d. In the multifilament configuration, the filaments 205-d may be geometrically organized and spaced across the cross-section of the synthetic string 200. In some cases, the multifilament configuration may not utilize the outer casing 210-d and may instead include only the multiple filaments 205-d wound together. In some examples, all of the filaments 205 may include biodegradable additives (e.g., all of the filaments may be biodegradable). In some examples, less than all of the filaments 205 may include biodegradable additives.

FIGS. 3A-3D illustrate several cross-sectional views of biodegradable synthetic string 300 (e.g., racquet string) in accordance with aspects of the present disclosure. As illustrated, FIG. 3A, FIG. 3B, FIG. 3C, and FIG. 3D depict various shape implementations of synthetic string 300. The synthetic string 300 may include one or more filaments 305 (e.g. an individually extruded mixture of the biodegradable synthetic string 300) and an outer casing 310. Though illustrated in each of FIG. 2A, FIG. 2B, FIG. 2C, and FIG. 2D, the outer casing 210 may not be present in every implementation of biodegradable synthetic string 300. Each of FIG. 3A, FIG. 3B, FIG. 3C, and FIG. 3D may represent a possible shape configuration, not limited to the whole applicable scope of biodegradable synthetic string 300. Although illustrated in FIG. 3A, FIG. 3B, FIG. 3C, and FIG. 3D as including one filament 305, each shape configuration may include a plurality of filaments and filament configurations (e.g., monofilament, center multifilament, center monofilament, and multifilament), for example as described with reference to FIG. 2 .

In some cases, the synthetic string 300 may include one or more filaments 305, where one or more of the filaments 305 may be manufactured to contain a petroleum based material and a biodegradable additive. In some examples, the synthetic string 300 may contain one or more filaments 305 and each filament 305 may be biodegradable. In some examples, the synthetic string 300 may contain one or more filaments 305 where all or less than all filaments 305 may include a biodegradable additive. In some cases, the outer casing 310 may include a petroleum based material and a biodegradable additive. In some cases, the outer casing 310 may not include a biodegradable additive.

FIG. 3A illustrates a circular shaped configuration of the synthetic string 300. In the circular shaped configuration, one or more circular shaped filaments 305-a may be present and a circular shaped outer casing 310-a may cover the exterior of the one or more filaments 305-a. In some cases, the circular shaped configuration may not utilize the outer casing 310-a and may instead only include the one or more filaments 305-a. In some cases, the one or more filaments 305-a may be of a shape other than circular and the outer casing 310-a may be circular shaped. In some other cases, the one or more filaments 305-a may be circular shaped and the outer casing 310-a may be of a shape other than circular.

FIG. 3B illustrates a hexagonal shaped configuration of the synthetic string 300. In the hexagonal shaped configuration, one or more hexagonal shaped filaments 305-b may be present and a hexagonal shaped outer casing 310-b may cover the exterior of the one or more filaments 305-b. In some cases, the hexagonal shaped configuration may not utilize the outer casing 310-b and may instead only include the one or more filaments 305-b. In some cases, the one or more filaments 305-b may be of a shape other than hexagonal and the outer casing 310-b may be hexagonal shaped. In some other cases, the one or more filaments 305-b may be hexagonal shaped and the outer casing 310-b may be of a shape other than hexagonal.

FIG. 3C illustrates a heptagonal shaped configuration of the synthetic string 300. In the heptagonal shaped configuration, one or more heptagonal shaped filaments 305-c may be present and a heptagonal shaped outer casing 310-c may cover the exterior of the one or more filaments 305-c. In some cases, the heptagonal shaped configuration may not utilize the outer casing 310-c and may instead only include the one or more filaments 305-c. In some cases, the one or more filaments 305-c may be of a shape other than heptagonal and the outer casing 310-c may be heptagonal shaped. In some other cases, the one or more filaments 305-c may be heptagonal shaped and the outer casing 310-c may be of a shape other than heptagonal.

FIG. 3D illustrates an octagonal shaped configuration of the synthetic string 300. In the octagonal shaped configuration, one or more octagonal shaped filaments 305-d may be present and a octagonal shaped outer casing 310-d may cover the exterior of the one or more filaments 305-d. In some cases, the octagonal shaped configuration may not utilize the outer casing 310-d and may instead only include the one or more filaments 305-d. In some cases, the one or more filaments 305-d may be of a shape other than octagonal and the outer casing 310-d may be octagonal shaped. In some other cases, the one or more filaments 305-d may be octagonal shaped and the outer casing 310-d may be of a shape other than octagonal.

The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details.

In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.

The description herein is provided to enable a person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein. 

What is claimed is:
 1. A biodegradable racquet string comprising: a petroleum based material; and a biodegradable additive blended with the petroleum based material.
 2. The biodegradable racquet string of claim 1, wherein the petroleum based material comprises one of nylon, polyester, or polyurethane.
 3. The biodegradable racquet string of claim 1, wherein the biodegradable additive comprises between 0.2 percent and 4 percent of the racquet string by weight.
 4. The biodegradable racquet string of claim 1, wherein the racquet string comprises a plurality of filaments.
 5. The biodegradable racquet string of claim 4, wherein the plurality of filaments are wound together.
 6. The biodegradable racquet string of claim 4, wherein the plurality of filaments are wrapped around one or a center monofilament or a center multifilament.
 7. The biodegradable racquet string of claim 4, wherein each filament of the plurality of filaments comprises the petroleum based material and the biodegradable additive.
 8. The biodegradable racquet string of claim 4, wherein at least one filament of the plurality of filaments comprises the biodegradable additive.
 9. The biodegradable racquet string of claim 1, wherein the racquet string comprises a monofilament.
 10. The biodegradable racquet string of claim 1, wherein a cross section of the racquet string has one of a round, hexagonal, heptagonal, or octagonal shape.
 11. The biodegradable racquet string of claim 1, further comprising at least one color additive.
 12. The biodegradable racquet string of claim 1, wherein the racquet string is capable of withstanding at least 120 pounds of tension. 